Perdition is useful in multi-node installations, where several mailstore servers may be accessed through the same hostname (either via round-robin DNS or a load balancer).

Perdition is also useful for offloading the SSL connection from the tomcat server, and handling it in the proxy. This can reduce the load on the mailstore server, as well as work around some IMAPSSL bugs.

Setting the ports

"Real" and proxied ports

In any perdition setup, there are 2 ports defined for every service. The real port is the port that tomcat listens on to handle connections. The proxied port is the port that perdition listens on for client connections. When perdition is configured, the client connects to the proxied port, and perdition connects to the tomcat server on the real port. The real ports can (and probably should) be blocked from access to the outside world by your firewall.

Port consistency

When configuring perdition in a multi server environment, all of the servers should have the same ports defined for the real and proxied ports. Failure to do so will prevent perdition from operating correctly.

Cleartext and encrypted connections

By default, the server will not accept IMAP and POP login over a cleartext (non-encrypted) connection.
If cleartext connections to the server are enabled, the perdition proxy will forward SSL connections to the cleartext port on the real server port, offloading the SSL processing from the tomcat server. This is the recommended configuration